What causes bad breath? - Mel Rosenberg4:14

View full lesson: http://ed.ted.com/lessons/what-causes-bad-breath-mel-rosenberg
Halitosis is a curse that has plagued humanity since ancient times. But what causes it, and why is it so universally terrifying? Mel Rosenberg outlines the basics of bad breath — and what you can do when it strikes you.
Lesson by Mel Rosenberg, animation by Andrew Foerster.